Sibling Rivalry
by E-Raptor
Summary: This is the sequal to "Clocks", so don't read this until you've read the first one!  The Doctor and Casadie are trying to settle their differences, but before they can an evil force tries the duo's loyalty to one another, possibly for good.
1. Chapter 1

**Hey everybody! Guess **_**who**_**? Ok, I know I was going to call this story "The Crystal Seas", but recent events have um…**_**reversed the polarity of the… **_**um… You know what? I just had a better idea to be honest with you. I **_**will **_**be writing a story under that title in the future, but for right now I have more important things for the Doctor and Casadie to be doing (Muahaha!) What's it gonna be? Angels? **_**Daleks**_**? SENTIENT CLOUDS OF EVIL THOUGHT? I guess you'll just have to keep reading! Also, I'm sorry it's taking so long for me to crank out this story, but I've been working on 5 different books right now, so it's kind of a mess in my head at the moment. Also, happy New Year and can't wait for the next season of Sherlock! Sorry, that's COMPLETELY off topic… Reviews are the reason I do this, so keep them coming! Love you guys and ENJOY! **

It was night on the TARDIS. That is, it was as close to being night as is possible on a TARDIS. Its (Until recently) lone resident had taken to turning off the lights for 12 hours out of the day. He often laughed at himself for "going native" as they say and adopting a few human customs. They didn't know how good they had it, being able to shut down for several hours every day. What he wouldn't give to stop thinking for that long.

The Doctor was sitting in his well-furnished study in the depths of his TARDIS. It was a nice room, decorated with a plush red carpet and dark brown walls. The shelves that adorned these walls were filled with do-dads and papers. Most of the books were in the library down the hall. The Doctor was sitting at a large mahogany desk at the center of the study and was trying with enormous difficulty to busy himself with adding some features to his sonic screwdriver. His mind was elsewhere however and he kept thinking about Cassie.

It had been an odd first conversation to be sure. The initial joy of having his sister practically come back from the dead had been brief. It was like some force beyond them both had held them together for a long time, then suddenly let go and Cassie had jumped back like a startled animal and her expression became unreadable. The Doctor was confused. What was wrong with her? He stepped toward her and tried a smile.

"Cassie, it's me!" She inhaled sharply and took several steps back until she was partially hidden from view by the main console. "Cassie? What's wrong?" She frowned, no, glared at him.

"400 years."

"What?"

"That's how long I waited for you." The Doctor stuttered, unsure what he should say. 400 years? Had it really been that long?

"Well I'm…I'm here now." This was apparently the wrong thing to say and Cassie took several threatening strides in his direction. This honestly frightened him. He had never associated his sister with a threat. She was getting closer now, forcing him to walk backward as she started shouting.

"But you weren't there then! You weren't there when I needed you! You never showed up when your entire race needed you! What were you doing, knocking about the universe in your out-of-date TARDIS? Something terribly important I expect! Enough to keep you from saving billions of lives!"

The Doctor now had his back to a wall and tried to get away from her, but her small form held him in place. She was so angry; you would think that after 400 years she would cool down a little.

"No, you're going to stay right here and listen!" She said as he tried to squirm around her. She forcibly grabbed his arm and pushed him back to the wall. He was so used to human strength that this burst of Gallifreyan force startled him. "I want to know something you double-faced, lying, careless, child of Time Lord." She hissed. "I want you to know that you're a Nanoi'Envae'Dosh, you Cri'Eali Rhy'Laut!" She was now ranting at him in Gallifreyan. The Doctor knew this was going to get messy unless he did something.

"Ok, you're right!" He said, cutting off another stream of insults. Casadie looked slightly confused. Clearly she hadn't anticipated an apology. The Doctor was extremely nervous. He decided to say his next few words in Gallifreyan. Perhaps that would prevent her from snapping again.

"Ni'si Sop'Aet, Ohn'Relue in Pontlottyn Krvas Salaene'Klaelan. Natea'Niat'Nuom."

(I'm sorry my sister. I have been living forever in despair and fear of the crimes I have committed against our home. It has made my soul turn dark.)

In Gallifreyan, especially his dialect, every word, every pause, and every syllable was the equivalent of a thousand human words. In just two sentences of perfectly spoken language, the Doctor had expressed the deepest regret and sorrow to Casadie. Whether or not she would accept it as the truth was another matter entirely. She stood there for a long time, her face inches from his. He honestly couldn't tell what she was thinking. She suddenly stepped back and hissed,

"Nuom'Niat'Natea."

(Your soul should be dark.)

With that she turned on her heels and disappeared up a flight of stairs into the deepest depths of the TARDIS.

With a sigh of exasperation the Doctor slid down the wall until he was sitting on the metal grated floor. He was very out of practice dealing with his younger sibling, but 400 years? No, it couldn't possibly have been that long. 200, maybe. No, more than that. 300? He groaned and ran his fingers through his hair. Yep. 400 years. Leave it to Casadie to never get the time wrong.

Now that he was away from her, he could finally think straight. He loved his sister; he always had, but now that she had suddenly showed up out of nowhere he could almost see her as an intrusion, an unwanted reminder of his past mistakes. It was so unfair! They were in the past! There was nothing he could do to change them! And it wasn't as if he didn't regret every second he spent enjoying the bounty of the universe as his own people were wiped out by his greatest enemy. The Doctor stood up and began to pace the main console room. His footsteps made a satisfying amount of noise in the large space. He hated this feeling, this sense that he was just a piece of driftwood caught up in the river of existence. Call him a control freak if you like, but the ability to choose whether or not something happened was what kept him going, the sense that his life in some way made those of others better.

He stopped stomping around the room and leaned forward heavily on the console. He covered his head in his arms and closed his eyes. If he were human he could have gone to sleep, but he wasn't human, and he would be spending the rest of his life fully aware of everything around him. What a shame then that most of what surrounded him was utterly miserable.

So ran Casadie's first day onboard the TARDIS. For the next few days it had been an awkward game of avoiding one another in any possible manner. When the Doctor heard his sister's light footsteps in a corridor he would dart into a random room and wait for her to pass. That was what brought him to his study in the first place. He hadn't been in there for months, quite possibly because he had simply run out of things to study. Now he sat, fiddling with his sonic and waiting for her to pass the room, but he could sense her presence lingering outside. What was she doing out there? Finally she moved on and he stood up and started pacing the room. What was he going to do about her? He hated to think about it, but he was undeniably stuck with her. She was his little sister, and as such his responsibility. That was of course added to the fact that they were the last Time Lords in existence. He had an unavoidable responsibility to her, no matter how she felt about it. Although he knew he couldn't hide from her for the rest of his life, he didn't feel ready to face her now. Let her cool off a bit beforehand, or better yet, let her make the first move. This got him thinking…

Casadie was fresh out of the Time War, and so had he been a couple regenerations ago. What had consoled him in his time of need? Realizing that it had been Rose, he quickly terminated that train of thought. Great, another old wound reopened… He huffed in frustration and flung himself back into his chair. He had a companion to help him through it. Casadie didn't. No, she did; she had him, although if her initial reaction to him was any indication she wouldn't be his companion any time soon. She had after all called him a Nanoi'Envae'Dosh Cri'Eali Rhy'Laut, which can be roughly translated as a traitorous, thoughtless, and self-serving child of a monstrous creature. The shame? It sounds worse in Gallifreyan.

The Doctor decided to think bigger about this. Yes, Rose had been the human that had helped him, but she was human. The human race as a whole had saved him from his own guilt. Maybe that's what Casadie needed. Earth was a big planet though, so where they would go was a whole other problem. England? America? Some random jungle?

No, they were both done with jungles for a while. The Doctor instinctively touched the scar on his neck with a light hand. It still hadn't healed completely and continued to seep occasionally when he was under stress. It was comforting for him to remember that Grace had cared enough about him to save his life. He doubted Casadie yet knew enough about her own race to know that the Doctor would have died had she not helped him. He would have actually died.


	2. The Library

**Hey everybody! I'll make this quick… As I've said I'm working on A LOT of writing right now, including some Sherlock fanfiction, some sequels to this Doctor Who story (Featuring the 11****th**** Doctor ****and**** Casadie!), as well as some of my personal writing. Sorry about the depressing nature of these chapters, but I'm having trouble getting Casadie out of her funk. Hopefully she'll be over it in a couple more heart-felt chapters and they duo can get on being fantastic Once again, that's for your reviews and I WILL in fact start mentioning people's reviews and I WILL answer your questions, so keep them coming!**

**-E.H.**

"Nanoi'Envae'Dosh!" Casadie shouted, slamming her fist into the wall of the TARDIS corridor. "Cri'Eali Rhy'Laut!" She continued, scraping her nails against a control panel hoping the buttons would come off to spite her brother. They didn't move except to make an overhead light at the far end of the hall flicker pitifully. She had run out of insults and simply screamed now, shouting and furiously shrieking at her own insignificance. Deep down she knew that no amount of cusses or death wishes would bring her planet, or her _family _back, but she had to do _something_ or she would explode.

She was a hunting dog without a fox to chase. At least in the Time War she could take her anger out on someone…a Dalek perhaps. She almost wished that one of the metal atrocities would appear in the corridor with her so that she could kill it with her bare hands. She would, too. And she would relish the look of horror on its face, well, its eye anyway. She was so dispirit for a victim.

And her brother? He would watch and see what he did to her. Casadie was fully aware of her bloodlust, her hatred, and her disgust toward her own flesh and blood, but she had grown up in war, killing, loneliness, rejection, and, worst of all, helplessness.

She had followed her brother, oh yes… She had followed him when he went to do his evil deed on their home world. She had followed him to see what he was planning. If only she could go back in time and tell herself what he was going to do… So what if the Time Lords were a little more warmongering? At least they would be alive! There were good people on that planet. She had friends and family there. Good people, friends and family that she watched _die_. No, not die, live to suffer a fate _worse_ than death. For a long time Casadie had thought that wasn't possible, but then she suffered it herself. 200 years she had wandered, isolated, through an empty cosmos, unable to die, but unable to bear her own existence. She knew he was out there somewhere, traveling, socializing, _forgetting_.

Casadie turned a corner in the corridors of the TARDIS and caught a glimpse of her brother's brown suit as he disappeared abruptly into a room to her left. The coward. He couldn't even face his own sister, let alone his past. As she passed the door he had entered she could feel his presence inside. She was a young female Gallifreyan with a knack for the telepathic. She was sure her brother could sense her on the other side of the door, but she didn't care. She looked to the right and was surprised to see a door there. She was _sure_ it hadn't been there before. She stared at it. It was a large door made of wood, like the kind you would find in a castle on Earth. There was a large ornate knocker made right in the middle. Curious and quite desperate for a distraction, she tried to pull it open but it wouldn't budge. She frowned and tried again. Nothing.

Without warning a series of Gallifreyan characters appeared across the surface of the knocker like they were being forged into molten metal. Though an extremely complex language, it could be roughly translated as, _the smell of old books, the sound of a scribe's hand, the student's fulfillment._

A psychic door? Casadie hadn't seen one of those in years. Concentrating on the words she began to imagine the particular scent of her father's old books. Obviously almost no information was still held in book on Gallifrey, but her father was an avid collector of them. She had study at the Time Lord academy on Gallifrey as well, so the sound of a pen across paper was no stranger to her either. The quiet scrape of the tip over fibrous pages was enough to bring back memories of a time before the war, before the Doctor left her. With her satisfaction of earning the right to fly a TARDIS, the door's lock clicked open. Casadie realized she had been crying. Throwing a nervous glance over her shoulder to be sure her brother didn't see her, she darted inside the room.

It was the most amazing thing she had yet seen in a TARDIS, which was quite an extensive list. It was a library, mostly… The walls were at least forty feet high on all sides and the room itself was as large as a gymnasium. Every square inch of the walls was _filled_ with books. Big books, small books, hard cover, paperback, electronic, there must have been over a million! Casadie spun in place, taking it all in.

What made this room special however was the swimming pool. It really didn't look like a swimming pool, it was more like an oasis, like someone had picked it up out of the desert and plopped it in a red-carpeted library, sand and all. It was about 20 feet squared, perfectly circular and emitting a soft blue glow that cast shimmering light on the surrounding walls. About five feet around the outside of the pool white sand seamlessly replaced the carpet and sand below the blue water.

Casadie slowly approached the oasis, not daring to make a sound in the silence of the library. She reached the sand and kicked off her shoes, letting the fine sand sift between her toes. She continued to walk until she stopped at the water's edge. She sat down and let her feet dip into the water. It was pleasantly warm and she closed her eyes. For the first time in four days she allowed her muscles relax. It was like carrying around a heavy backpack for several days before finally taking it off. She felt weightless.

Letting some sand fall through her fingers, she thought about where she stood. Looking back at the past she realized wasn't doing her any good. If anything it was greatening her suffering. She was a Time Lord, and as such had a significant number of years ahead of her and it would be best if she didn't spend them angry at everything. This was a new start, and she would make the best of it. Well, she would make the best of a world without her family or friends…or a home for that matter; or a goal…or a foreseeable future. How did he do it, her brother? How did he cope with this…this _feeling_? This feeling like the whole universe was so _empty_? She even had another Time Lord to travel with, but her brother had _no one_! Maybe the odd human, but an organism that low on the evolutionary ladder was simply too young to fully understand him.

A spasmodic sob escaped Casadie's lips. She would never see Gallifrey again. She would never see it's forests, it's seas, it's beautiful red grass again. She would never hold a conversation with more than one person in her native language ever again. She would never read a Gallifreyan book again, or hear a Gallifreyan song that she didn't sing herself, and she didn't think her brother would take kindly to that on his TARDIS. Then something really hit her. _She would never marry._ She was the last female Gallifreyan, and her brother was the last man, but he was her brother. _She would never fall in love._

That was the straw that broke the camel's back. Casadie curled into a ball and cried. She cried for a long time. Face it. Time was the one thing she had enough of.


End file.
